the mind > mental capacity > knowledge > conformity with what is known, truth > disregard for truth, falsehood > lack of truth, falsity > mistake [phrase] > by myself (2)
(I) tell (also am telling) a lie1910
colloquial. (I) tell (also am telling) a lie: I am mistaken (esp. as an introduction to a corrected restatement of what has just been said). Cf. I'm a…
I'm a liar1940
One who lies or tells a falsehood; an untruthful person. I'm a liar, (in trivial use) I am mistaken.